This dialog box is used to control the drawing of scale bars in most image
windows and in the model view window. The length of a bar is automatically
set to a
round number (usually, 1, 2 or 5 times a power of time) in the units of the
pixel size defined in the model header. The dialog is opened from the
Edit menu of the 3dmod Informoation window, or from the
View menu of the
Model View window when the program is started as 3dmodv.

The settings in this windows are stored between invocations of 3dmod along
with the user preferences, rather than in a model file. The settings are:

Draw scale bars can be used to turn the scale bars on and off. Bars
are drawn only when the dialog is open and this checkbox is on.

White bars can be turned on to get white rather than black bars. It
is not necessary to turn this on to get a white bar in the Model View window,
as long as an image is not being displayed there. In that case,
when the Model View window has a black or a white background, the scale bar is
automatically drawn as white or black, respectively, regardless of this
setting. However, if image display is on, then the scale bar is drawn as
black by default, and this checkbox can still be used to have it drawn as white.

Vertical bars can be turned on to get vertical instead of horizontal
bars.

Color ramp can be used to get a false color ramp instead of a black or
white bar. This bar provides a key when showing images or stored values with
false color. The colors will be based on the standard false color map in
3dmod, or on a custom map if one was loaded.

Invert ramp will reverse the direction of color ramp. Note that stored
values are displayed with an inverted color ramp, while the false color ramp
for image display can be inverted with the F11 hot key.

Minimum length controls the size of the scale bars by specifying their
minimum length in pixels.
The smallest round number is found that gives a bar at least this long.

Thickness sets the thickness of the bars in pixels.

The Position combo box allows you to place the bars in any one of
the four corners of a window.

Indentation in X and Y determine the distance of the bar from the
edges of the window and can be set to shift the bar farther away from
the corner in either direction.

When Make bar multiple of is turned on, the bars will always be set to
the value in the spin box times a power of ten, rather than to a multiple of
1, 2, or 5. This feature can be used to
get bars of intermediate length; for example, when a 20 nm bar is too short but
a 50 nm bar seems too long.

When Make bar exactly is turned on, the bars will always be set to
exactly the value in the text box, overriding the setting of Make bar
multiple of and regardless of the length in pixels. This feature is
useful for keeping the bar to a fixed size in real units when making a series
of snapshots (e.g., a movie in Model View) with a widely varying zoom. The
first time this is turned on, it will use the last scale bar length drawn.
This will be helpful if you get the bar to the desired size before turning
this option on.

At the bottom of the dialog appears a list of actual scale bar lengths in
whatever windows are open. Values are shown for the most recently active
(top) Zap, Slicer, and Multi-Z windows, as well as for the XYZ and Model View
windows if they are open.

Montage snapshots: You may need to adjust the scale bar
properties if you want to take a high-resolution montage snapshot of the Zap
or Model
View windows.
Scale bar size and indentation are automatically scaled up by
the montaging factor so that the bar will appear proportionally the same in the
snapshot as in the original window.
However, this scaled up bar must be located entirely in one of the montage
panels (e.g., in the bottom right quarter of the window if montaging by 4).
If the bar does not fit in a panel with the properties that you have set,
the program will first try to shift the bar toward the corner of the image
by reducing the indentation in the direction of the bar length
(X for a horizontal bar). If that change is not sufficient, it then tries to
shorten the bar by reducing
the minimum length of the bar in pixels to as little as half of the original
setting. A message is printed indicating either that such changes were made,
or that the bar cannot be drawn with the current settings. In the latter
case, or if you do not like the changes that were made, you can adjust the
settings yourself to position the bar completely within one panel.

In any case, the actual length of the
scale bar for the montage is printed on the terminal, since it is possible
for the length to be different from that in the original window.